If the cacheline may still be busy, atomically mark it for future release, and only if we can determine that it will never be used again, immediately free it. Closes: https://gitlab.freedesktop.org/drm/intel/issues/1392 Fixes:ebece75392("drm/i915: Keep timeline HWSP allocated until idle across the system") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Cc: Matthew Auld <matthew.auld@intel.com> Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> Cc: <stable@vger.kernel.org> # v5.2+ Link: https://patchwork.freedesktop.org/patch/msgid/20200306154647.3528345-1-chris@chris-wilson.co.uk (cherry picked from commit2d4bd971f5) Signed-off-by: Jani Nikula <jani.nikula@intel.com>